A very short time. Creon works locally in the GI track. It is not absorbed and does not accumulate in the system. The important thing is to take enough of the drug. As much as 10 pills before meals may be needed for an effect.
Very quick. Creon and other pancreatic enzyme preparations work within a few days when taken with meals to help you break down fats especially. Sometimes however the dose is not enough, do this may result in a longer time until symptoms get better while the dose is being adjusted.
Pretty quickly. Usually within a few days if taken in the right dose and for the right indication (chronic pancreatitis)